1. Field of the Invention
The present invention relates to an electric bending endoscope including an electric bending endoscope in which a bending portion is electrically bent to a state corresponding to an absolute position signal by operating a bending operation instruction portion outputting the absolute position signal.
2. Description of the Related Art
In recent years, there has been widely used an endoscope which is capable of observing an organ in a body cavity by inserting a thin and long insertion portion into the body cavity, and is capable of, when necessary, performing various medical treatments by using a treatment instrument inserted into a treatment instrument channel.
The endoscope is generally provided, on the distal end portion side thereof, with a bending portion which is bent in the up and down/left and right directions. The bending portion can be bent in a desired direction by performing a pulling and slackening operation of a bending wire connected to the bending portion.
Generally, the bending wire has been manually operated. However, in recent years, as disclosed, for example, in Japanese Patent Application Laid-Open Publication No. 2003-245246, there is also an electric bending endoscope in which the pulling operation is performed by using bending power unit, such as an electric motor.
In the electric bending endoscope, the bending portion is bent by such a way that the electric motor is rotated, for example, by using a joystick which is bending operation instruction unit provided in an operation portion and which outputs, for example, a bending instruction signal for an absolute position, and that a pulley is rotated by the rotation of the electric motor to pull the bending wire connected to the pulley.
The joystick instructs a bending position by being tilted. That is, the direction to which the joystick is tilted is a direction to which the bending portion is to be bent, and the tilting angle of the joystick is the bending angle of the bending portion. When the joystick is in the upright state where the tilting angle of the joystick is 0 degrees, the bending portion is in a non-bent state (linear state). Therefore, it is possible for an operator to easily grasp the bending state of the bending portion in the body cavity from the sense of hand fingers which hold the joystick.